Advanced democracies, it is commonly argued, are unable to prevent unwanted immigration because their sovereignty is “self-limited” by virtue of their normative, legal, and economic liberalism. This article challenges this claim by examining a critical test case that is at the heart of self-limited sovereignty arguments: guest worker recruitment in postwar Switzerland and West Germany. The author shows that, contrary to conventional wisdom, the unintended settlement of guest workers was not a universal given but instead was far less extensive in Switzerland than in West Germany. This difference in exposure to unwanted immigration, she argues, was the result of path-dependent processes that can be traced back to the inception of each country’s recruitment program. Whereas West German officials made no concerted effort to control settlement until the program’s termination, Swiss policy from its beginning was marked by state-enforced worker rotation and the prevention of family unification. To account for these critical differences in policy design, the article argues that each guest worker system was fundamentally shaped by two sets of factors. First, program design varied depending on whether or not political elites could draw policy lessons from past experience with temporary worker programs. Where past recruitment had resulted in unwanted settlement, as had been the case in Switzerland, political elites sought to adopt policy provisions designed to prevent the past from repeating itself. Where past policy failure was absent, as was the case in West Germany, policymakers were less concerned with preempting settlement. Second, recruitment policy reflected the degree to which policymakers were able to operate autonomously from cross-cutting interests. Whereas the West German government could pursue recruitment relatively insulated from both business and popular pressure, Swiss policymakers had to repeatedly accommodate both sets of actors, in the process devising a recruitment system firmly premised on the principle of worker rotation.